Sam Smith is one of our 2022 Stengl-Wyer Fellows. Sam studies rodent vocal mechanisms in the lab of Dr. Steven Phelps. In this blog, she talks about her wide interests in biology, the fascinating way rodent vocalizations work, and how her fellowship is assisting with her research.
Tell us where you came from before UT, and what you studied then?
My journey leading to grad school has been marked by a “try everything” approach. I began studying biology in earnest as an undergraduate at Harvard University where I majored in organismal and evolutionary biology. The summer after my freshman year, I lived in Tanzania for a month where I took courses in conservation, human-wildlife interactions, and large animal ecology. There, I was introduced to field work. Wanting to experience wet lab work, in my third year I joined the lab of Arkhat Abzhanov, an evolutionary-developmental biologist who studies vertebrate head development. My project focused on the mechanisms of facial elongation in Seba’s short-tailed bat (Carollia perspicillata). This work was part of a bigger project exploring mechanisms underlying diverse head shapes across leaf-nosed bats of the Americas (Phyllostomidae). When I graduated, I joined a contract-research organization to understand how industry research differs from that of academia. The company, inviCRO, does imaging studies for pharmaceutical and biotechnology companies. There, I was exposed to pre-clinical rodent research mainly focusing on Alzheimer’s and cancer. After two years, I decided to return to graduate school at UT.
You study rodent vocal mechanisms. Can you explain to us how this works?
Almost all terrestrial vertebrates (besides birds) use the same mechanism to make sounds. In the throat is an organ called the larynx, which helps protect the airway and is involved in making sounds. Inside the larynx, there are two flaps of tissue called the vocal folds (vocal chords in humans) which vibrate to make sound. The speed at which the folds vibrate dictates how high or low the sound is (sound frequency). There are inherent limits to this frequency range based on the size of the animal and the action of the throat muscles.
Rodents make some of the highest frequency sounds of all mammals, rivaled only by echolocating bats, and it has long been hypothesized that they use a different sound production mechanism to achieve these frequencies. Recent work suggests that mice are not vibrating their vocal folds at all. Instead, they make sounds like a flute: a stream of air hits a sharp edge (the edge of a flute opening or the edge of a laryngeal cartilage) which causes the air stream to vibrate, producing sound. This mechanism enables a much larger frequency range than vibrating the vocal folds.
What got you excited to study this area?
I’ve always been interested in mechanisms; how do new anatomical structures, physiology, or behaviors arise? Rodents provide some of the best opportunities to study mechanisms because there are many sophisticated techniques developed in laboratory rodents which can be applied to closely related species. Rodents are also incredibly diverse and speciose, providing opportunities for comparative work. I was drawn to studying sound production because rodents have this special ability to produce high frequency sounds and there is very little work on how sound production mechanisms vary across species that make different vocal calls.
Does Texas present a unique situation, challenge or benefit for your research?
The combination of our lab location here in Texas along with the collaborative relationships my advisor and I have developed with other researchers has allowed me to access rodents of southwestern US and central America. My dissertation has mainly focused on two closely related species of mice, one of which we catch here in Texas and the other which Is found in central America. The work I am completing as a Stengl-Wyer Fellow will expand our understanding of rodent vocal mechanism using species from Texas, Arizona, and Costa Rica.
How will being a Stengl-Wyer Fellow help advance your work?
Graduate students have many different responsibilities including but not limited to teaching, taking classes, managing labs, engaging in advocacy, and conducting research. Being a Stengl-Wyer Fellow has allowed me to focus on my research at a critical time in my graduate career. In my fellowship year I am completing a project where I comparatively characterize vocal muscles across 5 southwestern US and central American mouse species that make different types of vocalizations. This study will reveal molecular mechanisms underlying muscle physiology which will expand our understanding of how rodents make diverse sounds. The Stengl-Wyer Fellowship has connected me to other researchers and resources to support me at each stage of data collection, analysis, and disseminating results.
